SIK2 represses AKT/GSK3ß/ß-catenin signaling and suppresses gastric cancer by inhibiting autophagic degradation of protein phosphatases.
Mol Oncol
; 15(1): 228-245, 2021 01.
Article
in En
| MEDLINE
| ID: mdl-33128264
ABSTRACT
Salt-inducible kinase 2 (SIK2) is an important regulator in various intracellular signaling pathways related to apoptosis, tumorigenesis and metastasis. However, the involvement of SIK2 in gastric tumorigenesis and the functional linkage with gastric cancer (GC) progression remain to be defined. Here, we report that SIK2 was significantly downregulated in human GC tissues, and reduced SIK2 expression was associated with poor prognosis of patients. Overexpression of SIK2 suppressed the migration and invasion of GC cells, whereas knockdown of SIK2 enhanced cell migratory and invasive capability as well as metastatic potential. These changes in the malignant phenotype resulted from the ability of SIK2 to suppress epithelial-mesenchymal transition via inhibition of AKT/GSK3ß/ß-catenin signaling. The inhibitory effect of SIK2 on AKT/GSK3ß/ß-catenin signaling was mediated primarily through inactivation of AKT, due to its enhanced dephosphorylation by the upregulated protein phosphatases PHLPP2 and PP2A. The upregulation of PHLPP2 and PP2A was attributable to SIK2 phosphorylation and activation of mTORC1, which inhibited autophagic degradation of these two phosphatases. These results suggest that SIK2 acts as a tumor suppressor in GC and may serve as a novel prognostic biomarker and therapeutic target for this tumor.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Autophagy
/
Stomach Neoplasms
/
Signal Transduction
/
Protein Serine-Threonine Kinases
/
Phosphoprotein Phosphatases
/
Protein Phosphatase 2
/
Proteolysis
Type of study:
Etiology_studies
/
Incidence_studies
/
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Limits:
Animals
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
Mol Oncol
Journal subject:
BIOLOGIA MOLECULAR
/
NEOPLASIAS
Year:
2021
Document type:
Article
Affiliation country: